InvoicePlane is a self-hosted open source application for managing invoices, clients, and payments. Prior to 1.7.2, InvoicePlane stores an administrator-controlled custom_field_table value without validating it against the allowed custom-field table names. Mdl_custom_fields::used() later concatenates that stored value into the FROM table and WHERE column identifier positions, so opening the custom-field edit form executes a second-order SQL injection. The injection can query arbitrary schema data and can cause application errors or denial of service. This issue is fixed in version 1.7.2.